Process for the production of multi-layer coatings, comprising the successive steps: 1) applying a 10 to 35 [mu]m thick base coat layer to a substrate provided with an EDC primer, 2) applying a clear coat layer onto the base coat layer, 3) jointly curing the base coat and clear coat layers, wherein the base coat layer is applied in a first layer and in a second layer; the first layer comprises a modified water-borne base coat produced by mixing an unmodified water-borne base coat with a pigmented admixture component and the second layer comprises the unmodified water-borne base coat, wherein the admixture component contains one or more binders A, has a ratio by weight of pigment content to resin solids content of 0.05 : 1 to 1 : 1 and is mixed into the unmodified water-borne base coat in a ratio by weight of 0.1 to 1 parts of binder(s) A : 1 part of resin solids of the unmodified water-borne base coat, wherein the pigment content of the admixture component comprises at least one pigment which effectively reduces UV transmission and wherein the pigment content being such that UV light can penetrate through the base coat layer formed from modified water-borne base coat and unmodified water-borne base coat only in accordance with a UV transmission of less than 0.1% in the wavelength range of from 280 to 380 nm and of less than 0.5% in the wavelength range of from 380 to 400 nm.